Step 1: Call the Sprint International Desk at (817) 698-4199 and select option 3 to get a real live person.
Step 2: Tell them your Sprint phone number (the one that goes to your Tour) and answer any verification questions.
Step 3: They should now give you your unlock code. To unlock your phone all you need to do is.
- Options -> Advanced -> SIM Card
- Type 'mepdmep2' (a dialog should pop up)
- Enter your unlock code
- Reset your phone by pulling the battery
That's it! Kudos to Sprint for making this so easy, if a little hard to discover.